BELLEVUE, Wash. -- The Web isn't very old, but it's old enough for developers to have begun complaining about the restrictions imposed by HTML. Since HTML is intended to be interpreted by any computer with a browser, its creators deliberately limited the ways in which information to be transmitted by a Web server can be formatted.

These limitations pose particular problems for AS/400 system administrators trying to provide Web access to host-terminal applications. Although 5250-to-HTML converters have been on the market for several months, these products cannot compensate for the language's limitations, according to Chris Lategan, managing director of Advanced BusinessLink.

"If you look at all the production Web sites out there, they're not doing very sophisticated things at all," Lategan says. As an alternative, the Bellevue, Wash.-based company is using Java to translate 5250 screens into HTML without losing any function or needing any additional programming. BusinessLink for Java has been incorporated into the newest release of BusinessLink/Web, making it what may be the AS/400 market's first generally available Java applet.

BusinessLink for Java can take a 5250 data stream, convert it to a graphical user interface, and send it to the browser with a Java applet that will serve as a terminal emulator, providing a pop-up window in which the screen can be viewed. Features specific to AS/400 screens such as function keys are maintained.

Because of security concerns, browser developers such as Netscape and Microsoft have placed strict controls over Java applets running in their environments. For example, a Java applet cannot write to or read from any storage device on the client system. But because BusinessLink for Java works in connection with the BusinessLink/Web server, these restrictions can be circumvented without compromising security, Lategan says.

For example, a Java applet can send a message back to the server requesting that a file be downloaded to the system. If the user has configured their system to launch a particular application when a file of a certain type is downloaded, this request would ultimately result in an application being launched on the client system. On the other hand, files of types that are not configured within the browser will be blocked. Since the Web server designates the file type of the file being sent, the chance of a rogue file being downloaded is minimal.

BusinessLink for Java also manages the differences between AS/400 and PC-based printing. Each user who browses a site powered by BusinessLink/Web is assigned a unique ID number and print queue, which can expire at the end of a session or persist. Any print requests made to the AS/400 through the print server are funneled to this queue, thereby reducing the risk that a report could be delivered to the wrong user, Lategan says. Reports delivered spontaneously by an AS/400 application will remain in a persistent queue until the user signs on again.

Some of the features provided by BusinessLink for Java could be built in to Web servers in other ways, but in this case, programming would be required. Users of BusinessLink/Web, on the other hand, will be able to distribute all of their AS/400 applications over the Web with no additional programming. To allay security concerns, Advanced BusinessLink has created a proprietary encryption method to protect access to the Web server and shield sensitive data being transmitted, such as passwords for log-in.

BusinessLink for Java has three groups of potential users, Lategan says, but they all have one thing in common -- they're not currently AS/400 users. The product could be used to attract new customers, maintain relationships with existing customers, or create an intranet for employees who haven't traditionally had access to the AS/400.

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